Biology subjects

Peled, A.

Publications and source records attributed to Peled, A..

3 recordsLinked to original sources

bioRxiv2026

Bidirectional modulation of aging-associated cellular phenotypes by mitochondrial genome replacement

Mitochondrial dysfunction is a hallmark of cellular aging, but whether age-associated cellular decline can be functionally reversed remains unclear. Here, we applied mitochondrial genome replacement to replicative senescent fibroblasts and aged T cells derived from mice and humans. In senescent fibroblasts, replacement with mitochondria from young cells extended proliferative lifespan, whereas replacement with aged mitochondria accelerated proliferative decline, indicating bidirectional modulation of aging-associated phenotypes. In aged mouse T cells, mitochondrial genome replacement restored proliferative capacity and significantly enhanced antitumor activity following adoptive transfer into tumor-bearing mice. Similarly, mitochondrial genome replacement in aged human T cells enhanced cytokine production and shifted the transcriptomic programs toward a more youthful state. Collectively, these findings identify mitochondrial genetic integrity as a functional regulator of aging-associated cellular states and support the emerging view that mitochondria actively influence cellular aging trajectories.

Cell Biology↗

bioRxiv2020

Variability of dynamic patterns of cortical excitability in schizophrenia: A test-retest TMS-EEG study

BackgroundAltered stimuli processing is a key feature of schizophrenia. Application of concurrent transcranial magnetic stimulation (TMS) with electroencephalography (TMS-EEG) is an effective stimulus which allows direct measurement of the cortical response within a millisecond time resolution. Test-retest TMS-EEG studies present evidence of high reproducibility in healthy controls (HC), however, this stability of response has not been examined in schizophrenia. ObjectiveThe current study maps TMS-evoked patterns of cortical excitability in schizophrenia and examine whether these cortical patterns are amenable to change as symptoms of schizophrenia improve. MethodsOne hundred single-pulse TMS and 100 sham pulses were applied to frontal regions of 19 schizophrenia in-patients and 26 HC while electroencephalography data were simultaneously acquired. Medication and schizophrenia symptoms were reported. This protocol was repeated across three sessions (1 week apart) for each participant. The TMS-evoked cortical response of each participant was averaged and compared between groups. ResultsSchizophrenia patients showed reduced cortical excitability at early time-windows and increased excitability at later time-windows. Increased excitability at later windows was associated with heightened symptom severity. Schizophrenia patients showed an increased variability in cortical response over sessions relative to HC. Increased change in cortical response from session 1 to session 3 correlated with symptom improvement. ConclusionsSchizophrenia patients presented with abnormal patterns of cortical excitability when processing TMS stimuli. These dynamic patterns of cortical response were amenable to change as symptoms of schizophrenia improved. Further research into electrophysiological biomarkers of symptom improvement is hoped to improve current diagnosis and treatment models of schizophrenia.

neuroscience↗

bioRxiv2019

Phase-amplitude markers of synchrony and noise: A resting-state and TMS-EEG study of schizophrenia

The electroencephalogram (EEG) of schizophrenia patients is known to exhibit a reduction of signal-to-noise ratio and of phase locking, as well as a facilitation of excitability, in response to a variety of external stimuli. Here we demonstrate these effects in transcranial magnetic stimulation (TMS)-evoked potentials and in the resting-state EEG. To ensure veracity we used three weekly sessions and analyzed both resting state and TMS-EEG data. For the TMS responses our analysis verifies known results. For the resting state we introduce the methodology of mean-normalized variation to the EEG analysis (quartile-based coefficient of variation), which allows for a comparison of narrow-band EEG amplitude fluctuations to narrow-band Gaussian noise. This reveals that amplitude fluctuations in the delta, alpha and beta bands of healthy controls are different from those in schizophrenia patients, on time scales of tens of seconds. We conclude that the EEG-measured cortical activity patterns of schizophrenia patients are more similar to noise, both in alpha and beta resting state and in TMS responses. Our results suggest that the ability of neuronal populations to form stable, locally and temporally correlated activity is reduced in schizophrenia, a conclusion that is in accord with previous experiments on TMS-EEG and on resting-state EEG.

neuroscience↗